# Tagged Questions

The process of a liquid changing to a gaseous state

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### Water evaporation in a fountain

A friend of mine was riding next to a Buckingham Fountain in Chicago and the following question popped in his mind: How much water loss occurs due to evaporation. I can easily answer this question ...
117 views

### Why does saliva on the finger give correct direction of wind?

When we lick a finger and put it up in the air, the side that is cooled is the one facing the direction from which the wind is blowing. But consider this, if we take a cross section of the finger, ie ...
423 views

### Why can water evaporate? [duplicate]

Why can water evaporate below 100°C? Or, more in general, what is the mechanism behind the evaporation process in liquids?
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### Will a glass of water left in the fridge evaporate?

A commenter suggested that a glass of water left in a fridge would evaporate. I couldn't tell if this is true. I don't want to do the experiment since it would take too long; so I thought instead I'd ...
67 views

### How to calculate the minimum kinetic energy required by a surface molecule to escape the liquid (during evaporation)?

Evaporation occurs when surface molecules have enough Kinetic Energy to escape the surface of the liquid. Given a certain volume of liquid at a certain temperature, is it possible to determine this ...
106 views

### A theoretical model for evaporation occurring when wind is blowing over the surface of water

I've recently done an experiment in which I was studying the variation of the cooling rate of hot water in a draft (wind). The air was blow directly over the surface of the water (kept in a ...
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### How to calculate rate of evaporation of water?

How can I calculate how fast water will evaporate, if I know its temperature, the relative humidity, temperature, and speed of air flowing over it? Or if that's not enough information, what formulas ...
21 views

### What is the vapour pressure of carbon at room temperature?

The vapour pressure of carbon at 3642°C is one atmosphere (this is the sublimation temperature given in Wikipedia). At lower temperatures, the vapour pressure will be less, but of course it will ...
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### Which way the water evaporate faster?

-Hello everyone, Yesterday I was preparing some tomato sauce and, in order to remove some water from the sauce, I put it in a pot on the burner and waited until it started to evaporate. When I sow a ...
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### Good and bad collisions& cut energy in evaporative cooling (in atomic traps)

I read an article about evaprotive cooling and there are two (or three) things that I do not understand. 1.) In the article it says that the cut energy $E_{cut}$ (the energy a particle needs to ...
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### What is the nature of equilibrium between water and air in a sealed container that is heated above 100C?

In the case of a single substance (water), looking at the phase diagram is enough to conclude what happens upon heating: (source: WolframAlpha) But what if I have water and air (or some other gas) ...
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### Will water cool faster in an earthen pot if wetted externally?

If we put water in an earthen pot then water is being absorbed and it reaches the surface of the pot and then water evaporates and makes inside water cool. So is it right that if we wet the earthen ...
17 views

### Lengthening in-flight evaporation time of water droplet in air

How one can increase the in-flight evaporation time of sprayed water droplets in air without changing the thermodynamic conditions of the ambient air ( i.e. RH, T ). For instance mixing water with ...
30 views

### Can the air be cooled by blowing it around an earthern pot

It is clear that water gets cooled in an earthern pot thru evaporation etc. If we blow (fast) warm/hot air around such an enclosed pot (pot is further lying in say another bigger pot) so that the air ...
99 views

### Evaporation of water

Consider a cylinder that there is water inside it. The volume (and so the pressure) of the cylinder is adjustable by a piston. The thickness of the cylinder and piston is very negligible. The cylinder ...
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### Why water's temperature is less than air?

I measured the temperature of water and found that it's less than room temperature. I think evaporation is the main reason of it. Are there any reason except evaporation for the less temperature of ...
52 views

### The physics of a drying shirt

So, I've noticed this enough times to state my observations. I wash some shirts and hang them up to dry. Sometimes I need to wear one before they have completely dried. What I have noticed on ...
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### Can vaporization heat added to the whole volume of liquid before vaporizing it?

It seems, for example a volume of water is heated to boiling point, then part of the water is vaporized, while the remainder need much more heat to vapor, which means that part doesn't receive latent ...
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### What is the growth mode of thermal-evaporated aluminum on organic subtrates?

Does aluminum grow in an island mode or layer-by-layer mode on organic substrates which is amorphous? For example, on PMMA, fullerene or surfactant thin films. Can I predict the mode by comparing the ...
2k views

### Why does water feel cooler than air?

My first assumption was based on "evaporation causes cooling" but I realized that it is not the case as it is cooler even if I am submerged under it. Are all liquids generally cooler than air ? Just ...
110 views

### Why does an evaporating black hole always stay a black hole?

Stars can only collaps and form black holes if their masses are above the Chandrasekhar limit, $M>M_{\rm Pl}^3/M_{\rm hydrogen}^2$. When the universe eventually cools down enough, the black holes ...
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### Humidification Problem [closed]

Humidification Imagine that water is evaporating into initially dry air in the closed vessel shown schematically in Fig. 8.1-1(a). The vessel is isothermal at 25 C, so the water’s vapor ...
229 views

### Does high heat make a boiling pot of water evaporate faster?

According to another answer, the rate at which water evaporates depends on the temperature of both air and water, the humidity of the air, and the size of the surface exposed. The air ...
88 views

### Fluid filled open container in space/vacuum

I have water in a bottle, as I open it in space(or vacuum for that case ). From what I have read in books the water will instantly vapourize,as the vapour pressure of the water inside, far exceeds the ...
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### How much power is being actually delivered by an electric heater to a cooking pan?

I've been doing experiments on an electric heater heating a cooking pan filled with 2 litres of water, from 20°C to 70°C; now I'm trying to draw a theoretical heat transfer model thath should match ...
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### Which requires less energy, complete mechanical breaking or vaporization of matter?

Let's say we have a one kilogram piece of rock. Now if we want to separate each molecule from the other molecules making this piece of rock, which method requires the least energy while neglecting ...
50 views

### Methods to solve a vapor pressure equilibrium question with water on the moon? [closed]

"Imagine a tall column of water on the Moon, maintained at a temperature of 50°C and left to the open vacuum at the top. Up to what depth will the water continue to boil? The Moon's radius is 0.273 ...
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### Understanding the relation between pressure, ideal gas and, volume

I was given the following formula which is used for ideal gasses: $$pV = nRT$$ where: p:pressure V: volume n: number of moles R: gasconstant T: temperature now when speaking about vaporpressure ...
307 views

### What is the real cause of the boiling (forming of bubbles) of water?

I've got a question about the boiling of water. I'm a first year physics student and from the Netherlands. I've searched alot about the boiling of water and this confused me. Everyone said something ...
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### How can condensation be aided?

I was wondering if certain factors of water vapor condensation can be aided? For example, being able to increase the saturation of water vapor via a certain method, or another example would be having ...
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### What temperature is an evaporating cup of water at “room temperature”?

If I put 100 g of water in a cylindrical cup and I know it takes 2 weeks (lets say 1.2 × 106 seconds) at some RH/temp to completely evaporate in my room with a constant temperature, can I ...
165 views

### Heat Losses from water pan due to vaporisation before boiling

I'm studying heat transfer from an electric heater to a cooking pan (Stainless steel) filled with water; specifically, my problem is related to water vaporisation, as I've already found good models to ...
79 views

### Are particles that locally evaporate off water's surface at T = 100?

Water molecules can evaporate off a surface without needing to boil (How does water evaporate if it doesn't boil?). This is because surface particles are sometimes energetic enough to overcome ...
34 views

### Superheating Water Demonstration with a Vacuum

There are many Youtube videos which place a cup of water into a vacuum chamber and cause boiling around 0.020 atm, but I can't find any which show a vacuum-only "superheating" effect (to be clear, I ...
103 views

### Pressure inside tank while discharging water

I have two tanks, one initially fully filled with water (large tank) and the other one (smaller) is empty and has low pressure (say 0.5 bar) and the two tanks are connected from the bottom with pipe ...
68 views

### Bottle cap burst phenomenon [closed]

There is a trick you can do with a simple plastic water bottle: After putting the cap on as tight as you can, you twist the body of the bottle a few times so that it compresses the air in the bottle. ...
32 views

### Can there be net condensation into a pool of water?

I'm curious about the equilibrium of evaporation and condensation. Given that the surface area of a dehumidifier's evaporation coil at 4C is proportional to the rate of condensation, how would the ...
32 views

### Why doesn't water turn into liquid after boiling it? [duplicate]

Water's boiling point is 100 degree Celsius. So water shouldn't remain vapour under 100 degree Celsius. But water remains vapour even in the environment temperature. Why does that happen?
399 views

### Boilling a liquid in a closed container, less heat required?

If you boil a liquid with latent heat $L$ in a container of infinite volume (i.e. open to the universe) the heat required is: $$Q=Lm$$ Where $m$ is the mass of the liquid boiled. If however you boil ...
960 views

### Can evaporation occur in an air-tight container?

As the title states, can evaporation occur in an air-tight container? Could the liquid water turn into gas and just stay inside the container until it's opened? Would there be a limit to how much ...
351 views

### What is the equation that determines evaporation rate for water?

So I'm guessing it has to do with temperature of surface water, temperature of surrounding, surface area, humidity,... I always wondered if there was an equation to describe evaporation, never learned ...
504 views

### Water evaporation problem. Exercise from Feynman's lectures

I read lectures of Richard Feynman and try to solve problems and I have some trouble with a problem on water evaporation. A glass full of water is left standing on an average outdoor window in ...
250 views

### Calculating Evaporation Rate for Milk

So, I am kind of physics dumb. I have found the equation for water evaporation from a pool and I have been attempting to make work and make sense for creating a spreadsheet that will help me predict ...
56 views

### When drying paint brushes washed with water, which way is the best to orient them?

After washing my paint brushes with soap and water and rinsing them, in order to avoid damage to the bristles and the ferrules and the wooden handle, is it best to hang them bristles down and let ...
236 views

### Is water steam in air a case of liquid in gas solution?

Thinking of this question, I thought that the phenomenon of water evaporation into the air is totally analogous to the solid (say, salt) that is dissolved into a liquid (water). Indeed, in this ...
76 views

### If you charge water will the evaporation rate change?

If you take away electrons or add electrons to a body of water will the evaporation rate be changed? (Even if it's brief or the effect is small)
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### Confusion understanding relative humidity levels

I have difficulty in understanding how can the relative humidity of a mixture of air and water can be 100%. I understand that places like where i live have high relative humidity, so the place is more ...
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### Where are real limits of evaporative cooling?

There are many projects focused on utilising evaporative cooling for food preservation or computer cooling purposes. I have other thing in mind, however and that's cooling beer. Once you're outside, ...
According to Stephen Hawking's theory of black holes, once a sufficient mass has been lost through evaporation, the escape velocity $3 \times 10^8$ meters per second so light is able to escape from ...